J/A+A/581/A140 VISTA Orion mini-survey (Spezzi+, 2015)
The VISTA Orion mini-survey:
star formation in the Lynds 1630 North cloud.
Spezzi L., Petr-Gotzens M.G., Alcala J.M., Jorgensen J.K., Stanke T.,
Lombardi M., Alves J.F.
<Astron. Astrophys. 581, A140 (2015)>
=2015A&A...581A.140S 2015A&A...581A.140S (SIMBAD/NED BibCode)
ADC_Keywords: Molecular clouds ; Photometry, infrared
Keywords: surveys - stars: pre-main sequence -
open clusters and associations: individual: L1630N -
stars: formation - stars: protostars - ISM: clouds
Abstract:
The Orion cloud complex presents a variety of star formation
mechanisms and properties and is still one of the most intriguing
targets for star formation studies. We present VISTA/VIRCAM
near-infrared observations of the L1630N star-forming region,
including the stellar clusters NGC 2068 and NGC 2071 in the Orion
molecular cloud B, and discuss them in combination with Spitzer data.
We select 186 young stellar object (YSO) candidates in the region on
the basis of multi-color criteria, confirm the YSO nature of the
majority of them using published spectroscopy from the literature, and
use this sample to investigate the overall star formation properties
in L1630N. The K-band luminosity function of L1630N is remarkably
similar to that of the Trapezium cluster, i.e., it presents a broad
peak in the range 0.3-0.7M☉ and a fraction of substellar objects
of ∼20%. The fraction of YSOs still surrounded by disk/envelopes is
very high (∼85%) compared to other star-forming regions of similar
age (1-2Myr), but includes some uncertain corrections for diskless
YSOs. Yet, a possibly high disk fraction, together with the fact that
1/3 of the cloud mass has a gas surface density above the threshold
for star formation (∼129M☉/pc2), points toward a still
ongoing star formation activity in L1630N. The star formation
efficiency (SFE), star formation rate (SFR), and density of star
formation of L1630N are within the ranges estimated for Galactic
star-forming regions by the Spitzer "core to disk" and "Gould's
Belt" surveys. However, the SFE and SFR are lower than the average
value measured in the Orion A cloud and, in particular, lower than
that in the southern regions of L1630. This might suggest different
star formation mechanisms within the L1630 cloud complex.
Description:
Data for L1630 N were taken during the VISTA Science Verification (SV)
as part of the program "VISTA SV Galactic Mini-survey in Orion"
(PI: M. Petr-Gotzens; Petr-Gotzens et al., 2011Msngr.145...29P 2011Msngr.145...29P). This
survey consists of ZY JHKS images obtained during 14 nights between 16
October and 2 November 2009. The survey area is a mosaic of 20 VISTA
fields with each field containing 6 pointings that are mosaicked
together to form a so-called filled tile. The total survey covers
∼30 square degrees around the Orion Belt stars.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 94 172 Theoretical isochrones from Baraffe et al.
(1998A&A...337..403B 1998A&A...337..403B, Cat. J/A+A/337/403) and
Chabrier et al. (2000ApJ...542..464C 2000ApJ...542..464C) converted
into the VISTA photometric system
tablea2.dat 175 186 VISTA and Spitzer observed magnitudes for the
YSO candidates in L1630 N
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See also:
J/A+A/337/403 : Low-mass stars evolutionary models (Baraffe+ 1998)
J/AJ/135/966 : Circumstellar disk evolution in NGC 2068/71 (Flaherty+, 2008)
J/A+A/504/461 : YSOs in L1630N and L1641 (Fang+, 2009)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 13 A13 --- Age Age (1)
15- 19 F5.3 Msun Mass Mass
21- 24 I4 K Teff Effective temperature
26- 31 F6.3 mag ZmagD NextGen/AMES-Dusty model Z magnitude (2)
33- 38 F6.3 mag YmagD NextGen/AMES-Dusty model Y magnitude (2)
40- 45 F6.3 mag JmagD NextGen/AMES-Dusty model J magnitude (2)
47- 52 F6.3 mag HmagD NextGen/AMES-Dusty model H magnitude (2)
54- 59 F6.3 mag KsmagD NextGen/AMES-Dusty model Ks magnitude (2)
61- 66 F6.3 mag ZmagC NextGen/AMES-Cond model Z magnitude (2)
68- 73 F6.3 mag YmagC NextGen/AMES-Cond model Y magnitude (2)
75- 80 F6.3 mag JmagC NextGen/AMES-Cond model J magnitude (2)
82- 87 F6.3 mag HmagC NextGen/AMES-Cond model H magnitude (2)
89- 94 F6.3 mag KsmagC NextGen/AMES-Cond model Ks magnitude (2)
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Note (1): 1, 5, 10, 50 and 100 Myrs isochrones and the ZAMS (5 Gyrs).
Note (2): NextGen model-atmosphere code of Hauschildt et al.
(1999ApJ...512..377H 1999ApJ...512..377H) AMES-Dusty and AMES-Cond atmosphere models by
Allard et al. (2001ApJ...556..357A 2001ApJ...556..357A).
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Byte-by-byte Description of file: tablea2.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- ID Sequential number
5- 24 A20 --- Name Name (HHMMSS.sss+DDMMSS.ss)
26- 33 A8 --- Prev Object previously identified (1)
35- 39 A5 --- Class Lada class (2)
42 A1 --- l_Zmag Upper limit flag to the actual brightness of
the object on Zmag
43- 48 F6.3 mag Zmag ?=- VISTA Z magnitude (3)
50- 54 F5.3 mag e_Zmag ? rms uncertainty on Zmag
56 A1 --- l_Ymag Upper limit flag to the actual brightness of
the object on Ymag
57- 62 F6.3 mag Ymag ?=- VISTA Y magnitude (3)
64- 68 F5.3 mag e_Ymag ? rms uncertainty on Ymag
70 A1 --- l_Jmag Upper limit flag to the actual brightness of
the object on Jmag
71- 76 F6.3 mag Jmag ?=- VISTA J magnitude (3)
78- 82 F5.3 mag e_Jmag ? rms uncertainty on Jmag
84 A1 --- l_Hmag Upper limit flag to the actual brightness of
the object on Hmag
85- 90 F6.3 mag Hmag VISTA H magnitude
92- 96 F5.3 mag e_Hmag ? rms uncertainty on Hmag
98 A1 --- l_Ksmag Upper limit flag to the actual brightness of
the object on Ksmag
99-104 F6.3 mag Ksmag VISTA Ks magnitude
106-110 F5.3 mag e_Ksmag ? rms uncertainty on Ksmag
112-117 F6.3 mag [3.6] IRAC 3.6um magnitude
119-123 F5.3 mag e_[3.6] rms uncertainty on [3.6]
125-130 F6.3 mag [4.5] IRAC 4.5um magnitude
132-136 F5.3 mag e_[4.5] rms uncertainty on [4.5]
138-143 F6.3 mag [5.8] IRAC 5.8um magnitude
145-149 F5.3 mag e_[5.8] rms uncertainty on [5.8]
151-156 F6.3 mag [8.0] IRAC 8.0um magnitude
158-162 F5.3 mag e_[8.0] rms uncertainty on [8.0]
164-169 F6.3 mag [24] MIPS 24um magnitude
171-175 F5.3 mag e_[24] rms uncertainty on [24]
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Note (1): Specifies whether the object has previously been identified
by Flaherty & Muzerolle (2008AJ....135..966F 2008AJ....135..966F, Cat. J/AJ/135/966) (F08)
and/or Fang et al. (2009A&A...504..461F 2009A&A...504..461F, Cat. J/A+A/504/461) (FA09).
Note (2): The Lada classes marked with "?" are uncertain because the
corresponding KS magnitude is uncertain (i.e., photometric contamination,
large photometric errors, object truncated, or partially saturated, etc.).
Note (3): The "---" symbol indicates that the object has not been detected in
the given VISTA pass band.
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 22-Sep-2015